Access Tokens are not necessarily JWTs. We also don't
have to validate them as we only pass it on as an opaque
string.
This also means that we don't log the JTI access tokens
anymore.
We also simplify handling of oidc callbacks.
`sid` is a key that refers to the user's unique SSO session at the
Identity Provider, and the same key is present in all tokens
acquired by any Relying Party (such as Wonderwall) during that session.
Thus, we cannot assume that the value of `sid` to uniquely identify the
pair of (user, application session) if using a shared session store.
